1. Field of the Invention
The present invention relates to an information detecting device for a camera of the type using a film cartridge with a code pattern representative of information of a film encased within the film cartridge.
2. Description of the Prior Art
In photography, it been well known that a film magazine, cassette or cartridge is provided with coding representative of inherent information such as a film speed, etc. of a film encased in the film magazine, cassette or cartridge and that a camera is provided with a detecting device for reading out said film information. Said film information derived by the detecting device is automatically stored in the camera and used to represent an exposure data or to control exposures.
For instance, U.S. Pat. No. 4,173,401 discloses a camera provided with a film cartridge with a series of laterally spaced electrically conductive contacts and detection means with a series of laterally spaced electrical contact pins which correspond to a series of laterally spaced electrically conductive contacts, respectively, on the film cartridge. Some of the contacts on the film cartridge are coated with an electrically insulating cover so that they are electrically disconnected from the corresponding contact pins. Therefore, an electrically conductive and electrically non-conductive pattern is formed and represents a digital code representative of the film information.
The information picked up by these contact pins is applied to an electric circuit within the camera, decoded and stored.
The contact pins are retractably extended through the surrounding walls of a film chamber in the camera, which chamber houses a film cartridge, in such a way that the contact pins are brought into contact with the contacts on the film cartridge. In order to ensure positive contact between the contact pins and the contacts on the film cartridge, springs are provided so that the contact pins are normally biased to extend into the film chamber.
In order to ensure the smooth loading or removal of a film cartridge into or away from the film chamber, it is preferable that the contact pins are extended at the bottom of the film chamber rather than at the positions adjacent to the opening through which a film cartridge is loaded or removed. In the latter case, the contact pins are biased toward the opening of the film chamber.
When a camera back is opened to expose the film chamber of the type described and when a film cartridge is loaded, the film cartridge is pushed back by the contact pins biased under the forces of the springs so that it cannot be loaded at a predetermined position within the film chamber. Therefore, there has been a defect that it is difficult to withdraw a film from the film cartridge under these conditions and to engage it with a spool of the camera.